National Guard troops have begun arriving in Los Angeles on orders from President Donald Trump to stamp out protests that have broken out in recent days against federal immigration authorities seeking to carry out deportations in the region.

The Guard’s arrival marks a potentially volatile phase in Trump’s push to ramp up deportations and in his contentious relationship with state and local authorities.

The detention of the U.S. Army veteran and immigrant who obtained U.S. citizenship, punctuated a series of unusual events that have appealed to Trump supporters but outraged other Americans.